Thought I'd chip in my 2 cents about these issues..
Dice Cups: I honestly don't know why, but during the tournaments I've been to I've seen less than a handful of people use them. I've heard some of the same complaints in this thread come from people in my area (people slamming cups, dice / cup making too much noise, takes too long) but honestly I love mine.
I bought one of the leather cups from ffstore - I used it in a preseason match for my league and used it during the Chaos Cup this weekend. It was GREAT. None of my opponents complained that I was using it.
Novelty Dice: Block Dice or custom D6?
Most of the tournaments I've attended have "games workshop or NAF block dice only" written into the rules. I don't personally care for the icons on most of the alternate block dice, I guess I'm just so used to the NAF icons that other dice leave me confused - my porn bowl dice aren't including in that though

those things are hilarious and epic.
Custom 6 sided dice are VERY common near me. Although I will only use / collect dice that have a custom symbol on the "6". I will generally toss out dice with symbols on the "1" because I know it will only cause confusion at some point. Custom dice are also a fun reminder of tournaments that I've been to. Seeing the symbol show up when I'm rolling armor gives me instant gratification to know it's a good roll!
Bottom Line: I'm pro dice cups for everyone because they eliminate cocked dice and I'm pro custom d6 because they are more fun to look at
